Lecture Notes Dermatology - Graham-Brown, Robin, Burns, Tony

36 Fungal infections
Candida i nfection
Candidiasis (moniliasis, ‘ thrush ’ ) is a term applied
to infections of the skin and mucous membranes
by yeast - like fungi of the genus Candida . The most
common, Candida albicans , is a normal commensal
of the human digestive tract, where it exists in
balance with the bacterial flora. In its commensal
role, Candida sp. is present as budding yeasts. In
a pathogenic role, budding and mycelial forms are
usually present. It becomes pathogenic only when
situations favourable to its multiplication arise.
These include topical and systemic steroid therapy,
immunosuppression of any aetiology (e.g.
lymphoma, AIDS), broad - spectrum antibiotic therapy,
diabetes mellitus, and the apposition of areas
of skin to produce a warm, moist environment.
The diagnosis of candidiasis can be confirmed
by culture of swabs taken from the affected areas.
Buccal m ucosal c andidiasis
White, curd - like plaques adhere to the buccal
mucosa. If these are scraped off, the underlying
epithelium is inflamed and friable. It may be
treated with nystatin oral suspension, amphotericin
lozenges, miconazole oral gel or itraconazole
liquid.
Angular c heilitis ( p erl é che)
Angular cheilitis is an inflammatory process occurring
at the corners of the mouth (Figure 4.11 ). The
main factors involved in its causation, either alone
or in combination, include infection with Candida
sp. or staphylococci, and the development of
prominent creases at the angles of the mouth,
either as a normal consequence of age or in edentulous
individuals who do not wear dentures or
have ill - fitting dentures. Saliva is drawn into the
creases by capillary action, and salivary enzymes
macerate the skin, producing sore, moist areas.
In denture wearers, modification of the dentures
may help. Treatment with an imidazole/
hydrocortisone combination, e.g. miconazole/
hydrocortisone, is usually of benefit.
Chronic p aronychia
This is a chronic inflammatory process affecting
the proximal nail fold and nail matrix. It occurs
predominantly in those whose hands are repeatedly
immersed in water — housewives, bar staff,
florists, fishmongers. A sharp decline in the incidence
of this disorder in recent years is probably
related to more widespread use of mechanical
dishwashers, rather than the human variety, and
hand protection with washing - up gloves.
The clinical appearance is of thickening and
erythema of the proximal nail fold ( ‘ bolstering ’ ),
and loss of the cuticle (Figure 4.12 ). There is often
an associated nail dystrophy. Candida albicans
plays a pathogenic role, but bacteria may also be
involved. The absence of the cuticle allows access
of irritant substances, such as detergents, to the
area beneath the proximal nail fold, and this probably
contributes to the inflammatory process.
Figure 4.11 Angular cheilitis.